About 8% of chicken embryos die before hatching each year; the value is much higher in turkeys. Embryonic viability is influenced by a series of factors such as nutrition, hatching technology, egg quality and genetics. The nutritive components of the egg yolk are influenced by environmental and genetic factors and could affect the embryonic survival ability. The main goal of this study was to determine metabolite profiles in the egg yolk and to assess possible associations with hatchability.
A large number of hatching eggs were collected from 4 different lines (commercial white- and brown layer lines and experimental unselected lines). Based on estimated breeding values of hatchability traits in hens of aforementioned lines, 1073 egg yolk samples were collected to determine metabolite profiles using gas chromatography–mass spectrometry.
A total number of 105 different metabolites known in egg yolk, including fatty acids, amino acids, carbohydrates, steroids, glycerides, vitamins and organic acids were detected. The estimated heritability for different metabolites was in the range between 0 and 70%.
Significant differences were found between different lines. Compared to white layers lower amounts of saturated fatty acids and monounsaturated fatty acids were detected in brown layers’ egg yolks, whereas the content of polyunsaturated fatty acids, was higher in brown layers. A significant association between embryonic survival ability and the polyunsaturated fatty acids arachidonic acid and docosahexaenoic acid was found. These fatty acids are essential for the development of the embryonic brain and nervous system in precocial birds.
Furthermore, a significant positive association was observed between embryonic mortality and palmitoleic acid and it’s precursor palmitic acid, which are known to influence insulin content and glucose metabolite pathways during embryonic development.